For me the subsequent three are most definitely better.
1. Death Note
2. Monster
3. Code Geass
To be fair though, they are much shorter than OP, I think that when you put all of them together you get like 1/3 of OP chapters at this point, so the writing can be more consistent. Secondly, I personally enjoy battles of wits more than battles of strength, so the aforementioned three are perfectly suited for me.
There are other manga that I've been enjoying quite a lot recently. Bungou Stray Dogs and Black Butler come to mind first. I think the stories and the characters in them are very interesting and good.
Another pretty fun manga, nothing special to be honest though, is Black Clover. As I said it's nothing special but a pretty fun read
@Admiral Lee Hung can attest to it, and I've been enjoying it much more than OP recently.